Testing laboratory services highly depends on their revenue from loyal customers who come and do the testing. With so many competitors, institutions rely on their service quality. The quality of the laboratory divided into two parts, one of which is functional quality. Functional quality is a way where the product delivered to the customer. It may include aspects such as the timeliness of completion of a job, being responsive to customer needs, and continuous improvement in service. Regarding processing, timeliness associated with data availability, the degree to which customers have the data they need at the right time.
In this study, Hierarchical Timed Colored Petri Net used to model the testing process at one of the testing institutions in Indonesia. Simulation modeling is a useful tool to produce quantitative decision support in different application areas. This study examines the problem of waiting times for testing service through the building and validation of a computer simulation model. Using the CPN Tool for modeling, analysis, and visualization of the job flow within the service considered. The simulations performed to find out which parts of the process have the most critical time. Then by using Priority Queueing based on Shortest Processing Time, the simulation is conducted again to find out the impact of proposed strategies on waiting time and throughput rates.

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